Half life

Question 1

Why is ALPHA radiation used in smoke detectors?

Answer 1

• Very ionising to create the current.

* Least penetrating so will be blocked by smoke particles.

Question 2

Why is BETA used to TREAT cancer (Inside the body) ?

Answer 2

• Strongly ionising so it will kill the cells it is absorbed by.
• Moderately penetrating so it can pass through the whole tumour to kill all the cells without affecting healthy cells

Question 3

Why is GAMMA used to treat cancer (outside the body)

Answer 3

• Very penetrating so can pass 
through the body to reach the 
cancer cells. 
• Weakly ionising so it has less 
effect on the healthy cells.